Development of indicators of eutrophication for the Eastern Gulf of Finland

Transcription

1 Development of indicators of eutrophication for the Eastern Gulf of Finland Dr. Tatjana Eremina Russian State Hydrometeorological University

2 BSAP targets for the Gulf of Finland Indicator of eutrophication Target values Dissolved oxygen content, ml/l 2.17 Total Nitrogen, μmol/l (winter) Nitrogen (winter surface nitrite+nitrate) [mmol/l] Total Phosphorus, μmol/l (winter) Phoshorus (winter surface DIP) [mmol/l] Chlorophyll а, μg/l Summer (June-September) Secchi depth (transparency), m Summer (June-September) < < <4.37 5,42

3 RSHU monitoring in summer, RSHU monitoring stations in the Eastern Gulf of Finland Sailing catamaran Centaurus-II Measured parameters: - temperature - salinity - ph - diss. Oxygen - nutrient concentrations (PO4, NO2+NO3, Si), - chlorophyll a (surface and selected levels depending on turbidity) - transparency - phytoplankton biomass and species - primary production, - suspended matter - benthos - phosphates in bottom sediments

4 Chlorophyll a Seasonal variability in Eastern GoF meridian section (May, June, August) (upper dotted line average annual GES target, lowersummer GES target) Хлорофилл "а", мкг/л: Хлорофилл a: Хлорофилл-a, мкг/л: Chlorophyll -a: Examples of 2011, 2012, 2013, 2014 (typical picture): - an area of constantly elevated concentrations of Chl a in the shallow-water easternmost part of GoF the estuary effect

5 Chlorophyll a Comparability of Chl a data: - Finnish method for coastal water twice the Secchi depth - Russian method 3 Secchi depths (depth is always different!) Meaning evident differences in results indicators for Chl a must be developed taking into account difference in sampling methods

6 Maximal phytoplankton biomass in July- August for sub-areas: (II) inner Neva estuary, (IIIa) outer Neva estuary, (IIIb) offshore

7 Nutrients 2014 (seasonal variability) TOTAL PHOSPHORUS TOTAL NITROGEN

8 Secchi depth (transparency) Transparence, m 5,0 4,5 4,0 3,5 3,0 2,5 2,0 1,5 1,0 II+IIIa Median = Distance Weighted Least Squares Median 25%-75% Non-Outlier Range Outliers Ttransparence, m 6,0 5,5 5,0 4,5 4,0 3,5 3,0 2,5 2,0 1,5 IIIb Median = Distance Weighted Least Squares Median 25%-75% Non-Outlier Range Extremes HELCOM Target 5.42 m 0, , Transparency (Secchi depth) in Eastern GoF: Content of suspended matter in River Neva water is less than in the Neva Bay itself Transparency (turbidity) of the shallowwater part of GoF is exclusively determined by dynamic mixing processes.

9 Bottom oxygen depletion Eastern GOF Seasonal Oxygen depletion along GoF transect 2014 Maximum areas of hypoxic zones in the Eastern GoF were registered in 2010 Reason - large ice cover in winter and stable hot and no-wind weather in summer 2010

10 Bottom oxygen depletion Eastern GOF 2001, 2003, 2006, 2009, 2013, hypoxic conditions Example - st.4ugms (deepwater area of the Eastern GoF) oxygen conc. and salinity in the bottom layer in HELCOM Target 2,17 ml/l

11 3-dimensional eco-hydrodynamic model SPBEM [Savchuk, 2002, Neelov et al., 32, , Ryabchenko et al., 2016] Cyanobacteria Summer spp. Diatoms Autotrophs Si uptake Nutrient Sinking Grazing Mortality P Heterotrophs Excretion N Detritus Mineralization Inorganic N, P & Si Bottom output Mineralization, P-retention, denitrification Burial describes N, P and Si cycling in the coupled pelagic and sediment subsystems has 12 pelagic & 3 sediment state variables

12 Assessment scenarios of future ecosystem state of the GoF C1 no impact of invasive species; C2 with impact of invasive species

13 Thank you for attention

14 DIP, μmol/l DIP, μmol/l II+IIIa (bottom) Median = Distance Weighted Least Squares IIIb (bottom) Median = Distance Weighted Least Squares Long-term trends for bottom DIP and DIN for shallow (II+IIIa) and deep-water (IIIb) sub-regions for late summer in the Eastern GoF Median 25%-75% Non-Outlier Range Outliers Extremes DIN, μmol/l DIN, μmol/l II+IIIa (bottom) Median = Distance Weighted Least Squares Median 25%-75% Non-Outlier Range Outliers Extremes IIIb (bottom) Median = Distance Weighted Least Squares Median 25%-75% Non-Outlier Range Outliers Extremes St.Petersburg Vodokanal sewage treatment efforts